Outcomes of patients admitted to tertiary intensive care units after interhospital transfer: comparison with patients admitted from emergency departments

OBJECTIVES: To compare outcomes of patients admitted to tertiary-level intensive care units after interhospital transfer (IHT) with those of similar patients admitted from the emergency department (ED). DESIGN: Historical case-control study using data from the Australian and New Zealand Intensive Care Society Adult Patient Database (ANZICS APD), a quality-assurance dataset. PARTICIPANTS AND SETTING: 28882 patients aged 16 years or older admitted to an adult tertiary ICU in Australia or New Zealand between 1 January 1994 and 31 December 2003 with one of the eight most common diagnoses for IHT patients. Patients admitted directly to the ICU from another hospital (DIHT group) (n=9203) were matched by age, sex, APACHE II score and diagnosis with non-IHT patients admitted from the ED (ED group). RESULTS: Hospital mortality was higher in the DIHT group than in the ED group for patients with a diagnosis of multiple trauma (11.0% v 5.1%; odds ratio [OR], 2.3; 95% CI, 1.6- 3.34), respiratory infection (28.1% v 19.1%; OR, 1.66; 95% CI, 1.34-2.05), sepsis (38.7% v 28.7%; OR, 1.57; 95% CI, 1.34-1.83), intracranial haemorrhage (49.9% v 42.6%; OR, 1.34; 95% CI, 1.14-1.58), head injury alone (16.9% v 13.7%; OR, 1.28; 95% CI, 1.01-1.62), and cardiac arrest (59.3% v 53.2%; OR, 1.28; 95% CI, 1.06-1.56), but not overdose (3.9% v 3.6%; OR, 1.09; 95% CI, 0.72-1.67) or chronic obstructive pulmonary disease (19.8% v 22.5%; OR, 0.85; 95% CI, 0.63-1.15). Overall, the DIHT group had a higher intubation rate, longer ICU stay and higher rate of discharge to another hospital. CONCLUSIONS: Patients admitted to an ICU from another hospital have higher hospital mortality and longer stay than those admitted from the ED, with the differences varying between diagnoses. These differences are important considerations for resource allocation and triage, and as a measure of quality.